Are athletic records reaching their limits?

But some scientists say sporting records are starting to flatline and one day will become near impossible to beat without drugs, gene splicing or futuristic technology.

The men's long-jump world record was set in 1991, the men's pole vault record remains unbroken since 1994 and short-distance swimming's achievements have actually reversed since the drag-reducing bodysuit was banned in 2010.

"In all sports, what you see is a levelling off," says Steve Haake, director of Sheffield Hallam University's Centre for Sports Engineering Research.

Records continue to be broken in many sports, but the margins are getting smaller and smaller, he explained.

Geoffroy Berthelot with the INSEP sports institute in Paris looked at a history of Olympic records since the modern Games began in 1896.

He calculates that athletes have reached 99 percent of what is possible within the limits of natural human physiology.

By 2027, half of all 147 sporting events studied will have reached their estimated limits and will not be improved upon by more than 0.05 percent after that, according to Berthelot's mathematical estimate.

"Sports performances are reaching a physiological plateau," he said.

Reza Noubary of Bloomsburg University in Pennsylvania projects that the men's 100-metre sprint, seen as the benchmark measure of human acceleration and speed, can only have a top time of 9.4 seconds.

The "data suggests that human speed increases are decelerating and will eventually stop completely," said Noubary.

But, he cautioned, this prediction is based only on mathematics.

It does not take into account the emergence of exceptional runners such as Jamaica's Usain Bolt, who currently holds the record with 9.58sec.

"It's impossible for anybody to predict the magnitude of the freakiness of athletic talent," said Noubary.

"Bolt, it turns out, is a perfect example as he combines the mechanical advantages of taller men's bodies with the fast-twitch (muscle) fibres of smaller men."

Noubary also calculated that the long-jump record of 8.95m held by Mike Powell of the United States for the past 21 years, is likely to be broken only around 2040. Powell's exploit came nearly 23 years after Bob Beamon's own 8.90m record buster in the 1968 Mexico City Games.

"Yes, we can predict limits," added Haake, though these would "probably not" be reached within five or 10 years.

"In 50 years we will be very, very close."

Sometimes what makes the difference is not genes but technology, like the full-body swimsuits that saw an unprececented 25 records broken in 2008 and 47 in 2009, before they were banned.

Mark Denny, a mathematician from Stanford University, said in a 2008 report that race speeds in greyhounds and thoroughbreds had not increased in 40 to 60 years despite the availability of top breeding animals and performance-boosting drugs.

There are also those who believe that records will always continue to be broken, if only by the thinnest slivers of hundredths of a second.

"Imagine if it were ever decided to measure in the thousandths," said Ian Ritchie of Brock University's department of human kinetics in Canada, adding that predictions of limits are nothing new.

Before Britain's Roger Bannister ran the mile (1.6 kilometres) in under four minutes in 1954, "many assumed that it was a theoretical impossibility" -- some apparently predicted a human's lungs would simply burst.

The current record for a mile is 3:43.13.

If there is an absolute limit to the men's 100m sprint, many expect it to lie years away, and observers predict an exciting Olympics for London starting on July 27.

"The top 25 average coming into 2012 is already consistently below 10sec so expect fast performances and extreme rivalry," said Haake, just weeks after Bolt was beaten in a 100m trial by his training partner, Yohan Blake.